The Medicaid program in the city has expanded to a record 2.5 million recipients, a report revealed yesterday.

The Human Resources Administration said the number of citywide Medicaid recipients has risen for a fourth consecutive month, climbing 3 percent since June.

There are now 2,531,662 New Yorkers enrolled in the program, which provides medical benefits to the poor. It is funded by the federal, state and city governments.

The Medicaid rolls now contain 800,000 more city residents than when Mayor Bloomberg took office in January 2002 and the total number has increased during nearly every month of Bloomberg’s tenure.

City officials have argued that the expansion of the program is actually cost-effective. They assert that when patients at city hospitals aren’t covered by Medicaid, the city must pay the full tab instead of just 25 percent, which is the city’s share of the overall program.

“It is far more cost-effective to have city residents enrolled in Medicaid and taking blood-thinning drugs than having them show up at Kings County Hospital needing a triple bypass,” said mayoral spokesman Jordan Barowitz.

Bloomberg has in the past refused to recommend cutting benefits, instead asking in vain for state lawmakers to pick up a larger share of the Medicaid burden.

Medicaid experts generally believe the rise in rolls should taper in coming years, but the federal government might then shift more of the costs to the states.